用于热阴极的热子绝缘层研究

研究了热子涂层的原材料粒度对热子绝缘层质量的影响,粒度过细或过粗,涂层附着不均匀,烧结后涂层表面开裂、起皮、粗糙、掉粉严重。采用粒度级配的配比方案制备了氧化铝涂层,电镜分析表明,涂层致密,质量得到明显改善;与原有工艺相比,氧化铝涂层抗压能力提高了1倍。     

拉盖尔-高斯光束入射石英基底石墨烯涂层的透射光强分布特性研究

石墨烯材料在光学领域的特性吸引了众多学者进行研究。本文基于角谱衍射理论建立了拉盖尔-高斯光束入射石英基底石墨烯涂层的双层结构模型,研究了拉盖尔-高斯光束通过该模型的透射光强分布特性,分析了改变石英基底的方向自相关长度、拉盖尔-高斯光束的拓扑荷数和石墨烯涂层的厚度对拉盖尔-高斯光束入射该模型的光强分布影响,且搭建了实验来进行验证,将其结果进行对比。结果表明：随着石墨烯涂层厚度增加,拉盖尔-高斯光束透过的光强随之减弱,当石墨烯涂层的厚度大于20 nm时,光强强度明显减弱。当石英基底的方向自相关长度增大时,光束受粗糙面影响变大,光强分布中暗斑变多。本文研究结果可以为石墨烯材料光学特性的研究提供支撑。     

Modulation of Intracellular Oxygen Pressure by Dual‐Drug Nanoparticles to Enhance Photodynamic Therapy

Oxygen plays an essential role in the photodynamic therapy (PDT) of cancer. However, hypoxia inside tumors severely attenuates the therapeutic effect of PDT. To address this issue, a novel strategy is reported for cutting off the oxygen consumption pathway by using sub‐50 nm dual‐drug nanoparticles (NPs) to attenuate the hypoxia‐induced resistance to PDT and to enhance PDT efficiency. Specifically, dual‐drug NPs that encapsulate photosensitizer (PS) verteporfin (VER) and oxygen‐regulator atovaquone (ATO) with sub‐50 nm diameters can penetrate deep into the interior regions of tumors and effectively deliver dual‐drug into tumor tissues. Then, ATO released from NPs efficiently reduce in advance cellular oxygen consumption by inhibition of mitochondria respiratory chain and further heighten VER to generate greater amounts of ¹O₂ in hypoxic tumor. As a result, accompanied with the upregulated oxygen content in tumor cells and laser irradiation, the dual‐drug NPs exhibit powerful and overall antitumor PDT effects both in vitro and in vivo, and even tumor elimination. This study presents a potential appealing clinical strategy in photodynamic eradication of tumors.     

Lead‐Free Cs2BiAgBr6 Double Perovskite‐Based Humidity Sensor with Superfast Recovery Time

Lead halide perovskites have demonstrated outstanding achievements in photoelectric applications owing to their unique properties. However, the moisture sensitivity of lead halide perovskite has rarely been developed into an applicable humidity sensor due to the intrinsic instability and toxicity issue. Herein, as a highly stable lead‐free perovskite, a Cs₂BiAgBr₆ thin film is chosen to be the active material for humidity sensor due to its extraordinary humidity‐dependent electrical properties and good stability. This Cs₂BiAgBr₆ thin film humidity sensor demonstrates a superfast response time (1.78 s) and recovery time (0.45 s). The superfast response and recovery properties can be attributed to the reversible physisorption of water molecules, which can be easily adsorbed onto or desorbed from the thin film surface. Moreover, the sensor also shows an excellent reliability and stability properties as well as logarithmic linearity in a relative humidity's range of 15% to 78%. The lead‐free Cs₂BiAgBr₆ perovskite possesses great potential for application in real‐time humidity sensing.     

Fused Cyclopentadithienothiophene Acceptor Enables Ultrahigh Short‐Circuit Current and High Efficiency >11% in As‐Cast Organic Solar Cells

A new method to synthesize an electron‐rich building block cyclopentadithienothiophene (9H‐thieno‐[3,2‐b]thieno[2″,3″:4′,5′]thieno[2′,3′:3,4]cyclopenta[1,2‐d]thiophene, CDTT) via a facile aromatic extension strategy is reported. By combining CDTT with 1,1‐dicyanomethylene‐3‐indanone endgroups, a promising nonfullerene small molecule acceptor (CDTTIC) is prepared. As‐cast, single‐junction nonfullerene organic solar cells based on PFBDB‐T: CDTTIC blends exhibit very high short‐circuit currents up to 26.2 mA cm^?2 in combination with power conversion efficiencies over 11% without any additional processing treatments. The high photocurrent results from the near‐infrared absorption of the CDTTIC acceptor and the well‐intermixed blend morphology of polymer donor PFBDB‐T and CDTTIC. This work demonstrates a useful fused ring extension strategy and promising solar cell results, indicating the great potential of the CDTT derivatives as electron‐rich building blocks for constructing high‐performance small molecule acceptors in organic solar cells.     

Synthesis of Metal Oxide Nanoparticles by Rapid,High‐Temperature 3D Microwave Heating

Microwave‐assisted fabrication has propelled the recent synthesis and processing approaches of various nanomaterials. However, in most previous studies, the synthesis temperature is limited to below 1100 K, which restricts its application. Here, a rapid, in situ 3D heating method to manufacture well‐dispersed metal oxide nanoparticles on a 3D carbonized wood (denoted as C‐wood) host using microwaves as the driving power is reported. The moderate electronic conductivity of C‐wood contributes to the local Joule heating and the good thermal conductivity guarantees the rapid 3D heating of the overall material. The temperature of the C‐wood increases from room temperature to ≈2200 K in 4 s (≈550 K s^?1), stabilizing to 1400 K, and then cooling back down to room temperature within 2 s. The preloaded precursor salts rapidly decompose and form ultrafine (≈11 nm) metal oxide nanoparticles on the surface of the C‐wood during the rapid quenching. The process takes place in air, which helps prevent the metal oxides from being reduced by the carbon. The 3D heating method offers an effective route to the rapid and scalable synthesis of metal oxide nanoparticles.     

任务驱动法在运算放大器教学中的应用

本文采用任务驱动教学法,通过军事实例将积分、微分、求和、求差等运算放大器的其他应用,串成一条线,设置成一个具体的任务,并将任务分解为层层递进的子任务.在教学过程中,围绕每个子任务的提出和解决展开学习,以子任务的完成结果检验和总结学习过程.教学实践表明,该方法有助于充分调动学员学习的积极性.     

芳烷基酚树脂玻纤增强材料性能的研究

用芳烷基酚树脂与玻璃纤维布制成纤维增强材料，研究了引材料的高温热老化性能和在３０－５０％热沸太航热醋和含氯离子的热沸醋酸下的腐蚀性能。     

Electron impact mass spectral fragmentation of 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]benzothia zepin-1-ones

The mass spectrometric behaviour of nine 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]b enzothiazepin-1-ones has been studied with the aid of mass-analysed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization. All compounds show a tendency to eliminate a neutral chlorine atom, or a chloroketene, or neutral propene, or styrene or substituted styrene molecule, plus Cl and/or H (or Cl) atom(s), to yield [M-Cl]+ ions, 2,3-dihydro-1,5-benzothiazepine derivative ions, 4,5-dihydro-5H-1,5-benzothiazepin-4-one ions which can further lose CO to give 1,4-benzothiazine ions. Both molecular ions and [M-Cl]+ ions show a tendency to eliminate an ethyl or benzyl/substituted benzyl radical to produce 2,2a-dihydro-1H-azeto[2,1-c][1,4]benzothiazin-1-one ions. The [M-Cl]+ ions could undergo rearrangement to yield 2,2a-dihydro-1H-azeto[2,1-d][1,5]benzothiazepin-1-one ions, 2,2a,3,4-tetrahydro-1H-azeto[1,2-a]quinoline ions or 1,1a,2,3-tetrahydro-azirino[2,1-d][1,5]benzothiazepine ions by loss of an ethane or a benzene/substituted benzene, a SH radical or a CO molecule. The molecular ions could also undergo rearrangement reactions to form other small fragment ions.     

一种香豆素化合物的结构鉴定

一种香豆素化合物的结构鉴定陈望忠焦克芳（北京军事医学科学院毒物药物研究所，北京１００８５０）关键词２，１５－十六烷二酮３－乙酰基－６－乙氧羰基－５－羟基－４，７－二甲基香豆素ＮＭＲ中图分类号Ｏ６５６．２２麝香酮是麝香中的主要成分之一，Ｓｔｏｌ［１］采...